زيد قام
Zayd rose.
Here «زيد» can be parsed as a mubtadaʾ whose predicate is a verbal clause. If one reconstructs «قام زيد» as the original, the later Zayd would instead serve as the verb's agent; after fronting, the verb may involve a covert pronominal subject.
The objection is that treating the reconstruction «قام زيد» as mandatory in every case overlooks important differences between mubtadaʾ, verbal agent, pronoun, and the rhetoric of reinforced attribution.